1. In a large bowl, combine sour cream and lime juice; season with salt and pepper. Transfer half the mixture to another container; set aside for serving. Toss cabbage, scallions, and minced jalapeno with remaining sour-cream mixture. Season again with salt and pepper.

2. In a large nonstick skillet, heat oil and remaining jalapeno half over medium-high heat; swirl to coat bottom of pan. Season fish on both sides with salt and pepper. In two batches (starting with larger pieces), cook fish until golden brown on all sides, 5 to 6 minutes. Discard jalapeno.

3. Meanwhile, warm tortillas according to package instructions.

4. To make tacos, fill tortillas with fish, and slaw. Drizzle with reserved sour-cream mixture. Serve immediately.


Note: For a toasted flavor, quickly heat tortilla over a gas burner until blistered in spots, holding it with tongs. Immediately place on a plate covered with the towel. This will steam the tortillas and further their flexibility.